1. Field of the Invention
The present invention relates to an optical navigation sensor device and an image processing method using a 2-dimensional sequential image process, and more particularly to an optical mouse capable of converting respective voltage values of pixels of an image produced therefrom into digital voltage values each having a certain bit value through a pre-process, in order to prevent the pixel values from being varied, thereby accurately tracing a motion thereof, and an image processing method using the optical mouse.
2. Description of the Related Art
An optical mouse is a peripheral device for a computer for indicating the position of a pointer on the screen of a display unit included in the computer. Under the condition in which such an optical mouse is laid on an optional support surface, such as a table surface, made of a certain material, it performs a signal processing operation for a light reflected from the support surface after being emitted from a light emitting diode installed in a body of the optical mouse in order to detect respective shifted amounts of the optical mouse in X and Y-axes, and moves a pointer on the screen of a display unit in X and Y-axis directions through the display unit.
Although such an optical mouse operates normally on a general mouse pad having a distinct pattern while exhibiting a low reflectance, as shown in FIG. 1a, it has a problem in that it operates unstably on a support surface, such as a gel (yellow) pad, exhibiting a severe scattering of light, as shown in FIG. 1b. 
As a conventional optical mouse control method for solving such a problem, a method has been proposed which is adapted to convert light beams incident onto respective pixels after being reflected from a support surface, on which an optical mouse is laid, into digital voltages values of 4 to 8 bits, in order to measure the directionality of the optical mouse.
In the case of this optical mouse control method, however, there may be noise components in digital voltage values due to a micro variation in light amount of pixels and noise generated in an analog circuit used in the optical mouse control method. For this reason, the digital voltage value of each pixel may vary even when the optical mouse does not move. As a result, it is impossible to accurately and effectively measure the directionality of the optical mouse.
In order to solve this problem, another optical mouse control method has been proposed. In accordance with this method, a light beam incident onto each pixel after being reflected from a support surface is converted into a digital voltage value of 4 to 8 bits which is, in turn, compared with the digital voltage values of other pixels, so as to determine whether the pixel is light or dark (1 or 0), as shown in FIGS. 2a and 2b. Thus, each pixel is set to have a 1-bit value corresponding to the light or darkness thereof. Based on the 1-bit value, the directionality of the optical mouse is measured.
In this conventional mouse control method, however, the directionality of the optical mouse is emphasized in a particular direction in accordance with which peripheral pixels are compared with the current pixel in association with brightness. For this reason, although the optical mouse exhibits superior navigation characteristics in the particular direction, it exhibits inferior navigation characteristics in other directions.